This invention is in the field of devices for percutaneous insertion into a vessel of the human body to place a stent at the site of an obstruction in that vessel.
Stents are well known devices for placement in vessels of the human body to obtain and maintain patency of that vessel. The greatest use for stents has been for placement within a stenosis in a coronary artery. When a stent is used for treating a coronary artery stenosis, it has always been necessary to first place a guide wire through the stenosis. The next step in the stenting procedure is typically to pre-dilate the stenosis with a balloon angioplasty catheter that is advanced over that guide wire. The balloon angioplasty catheter is then removed and a stent delivery system that includes the stent is advanced over the guide wire and the stent is then deployed at the site of the dilated stenosis.
Recent improvements in the design of stent delivery systems has made it possible to eliminate the step of pre-dilatation for the treatment of many classes of stenoses. The delivery of a stent to the site of a stenosis without pre-dilatation has been given the name xe2x80x9cdirect stentingxe2x80x9d. However, even with direct stenting, a guide wire is still required as a precursor to advancing the stent delivery system over that guide wire to place the stent at the site of a stenosis.
The present invention is a stent delivery system that uses a short section of a guide wire that is fixedly attached to a distal section of a balloon angioplasty catheter. By not having a guide wire that slides through the balloon of the balloon angioplasty catheter, the balloon on which the stent is mounted can have a reduced diameter. Therefore, the outside diameter of the undeployed stent mounted onto that balloon is also minimized. This provides a minimum profile, i.e., a minimum outside diameter, for the stent. A minimum profile at the distal section of the stent delivery system is highly advantageous for improving the percentage of cases that can be treated by means of direct stenting; i.e., without requiring pre-dilation of a stenosis. Another advantage of the present invention is that a separate guide wire is eliminated thus saving the cost of such a guide wire. Additionally, the time to perform a stent delivery procedure is reduced because a guide wire does not have to be placed prior to using the stent delivery system to place the stent at the site of a stenosis.
Thus an object of the present invention is to provide a means for placing a stent within a vessel of the human body without requiring a separate guide wire thus saving the cost of the guide wire and also saving the time required to place a separate guide wire through an obstruction such as an arterial stenosis.
Another object of the present invention is to reduce the outside diameter (i.e., the profile) of the distal section of the stent delivery system so as to optimize the capability of the stent delivery system for direct stenting.
Still another object of the present invention is to have a guide wire fixed at the end of a balloon angioplasty catheter with a stent mounted onto the catheter""s inflatable balloon and further that the length of the cylindrical portion of the inflated balloon that extends beyond each end of the stent (the xe2x80x9cballoon overhangxe2x80x9d) is less than 1.0 mm, preferably less than 0.5 mm and optimally 0 mm; the minimum balloon overhang being advantageous for reducing the probability of arterial wall dissection beyond the edges of the stent when the balloon is inflated.
These and other important objects and advantages of this invention will become apparent from the detailed description of the invention and the associated drawings provided herein.